Frozen Section for Detection of Lymph Nodes After Cervical Injection with Indocyanine Green (ICG) for Sentinel Lymph Node Technique in Endometrial Cancer Staging

Impact of obesity in the identification of the sentinel lymph node in endometrial cancer: a retrospective, monocentric study and literature review

PURPOSE

To evaluate the sentinel lymph node (SLN) protocol for staging endometrial carcinomas, assessing its impact on surgical management, and determining indications for adjuvant therapies. The study also examines factors that may influence SNL mapping, particularly focusing on the failure of the technique due to obesity.

METHODS

A retrospective analysis was conducted on the medical records of patients with a histological diagnosis of endometrial carcinoma, who underwent surgical staging with SLN biopsy. The lymph node status was compared between non-obese (group 1) and obese (group 2) patients.

RESULTS

71 women were included in the study, of which 33 were non-obese (46.5%) and 38 were obese (53.5%). The failure detection rate was higher in obese patients (14, 36.8%) compared to non-obese patients (5, 15.2%) (p = 0.039). The risk of mapping failure increased by 1.6 times for every 5-unit increase in body mass index (BMI) (OR 1.672, 95% CI 1.024-2.730, p = 0.040). BMI was confirmed as an independent risk factor for mapping failure in both univariate (OR 3.267, 95% CI 1.027-10.395, p = 0.045) and multivariate analyses (OR 5.779, 95% CI 1.320-25.297, p = 0.020).

CONCLUSION

SLN detection in obese patients requires great care, as obesity may alter the sensitivity of the technique.

Low-Volume Metastases in Apparent Early-Stage Endometrial Cancer: Prevalence, Clinical Significance, and Future Perspectives

Endometrial cancer (EC) is the most diagnosed gynecologic malignancy, and its incidence and mortality are increasing. The prognosis is highly dependent on the disease spread. Surgical staging includes retroperitoneal evaluation to detect potential lymph node metastases. In recent years, systematic lymphadenectomy has been replaced by sentinel lymph node (SLN) biopsy and ultrastaging, allowing for the detection of macrometastases, micrometastases, and isolated tumor cells (ITCs). Micrometastases and ITCs have been grouped as low-volume metastases (LVM). The reported prevalence of LVM in studies enrolling more than one thousand patients with apparent early-stage EC ranges from 1.9% to 10.2%. Different rates of LVM are observed when patients are stratified according to disease characteristics and their risk of recurrence. Patients with EC at low risk for recurrence have low rates of LVM, while intermediate- and high-risk patients have a higher likelihood of being diagnosed with nodal metastases, including LVM. Macro- and micrometastases increase the risk of recurrence and cause upstaging, while the clinical significance of ITCs is still uncertain. A recent meta-analysis found that patients with LVM have a higher relative risk of recurrence [1.34 (95% CI: 1.07-1.67)], regardless of adjuvant treatment. In a retrospective study on patients with low-risk EC and no adjuvant treatment, those with ITCs had worse recurrence-free survival compared to node-negative patients (85.1%; CI 95% 73.8-98.2 versus 90.2%; CI 95% 84.9-95.8). However, a difference was no longer observed after the exclusion of cases with lymphovascular space invasion. There is no consensus on adjuvant treatment in ITC patients at otherwise low risk, and their recurrence rate is low. Multi-institutional, prospective studies are warranted to evaluate the clinical significance of ITCs in low-risk patients. Further stratification of patients, considering histopathological and molecular features of the disease, may clarify the role of LVM and especially ITCs in specific contexts.

Diagnostic accuracy of frozen section and patterns of nodal spread in high grade endometrial cancer: A secondary outcome of the SENTOR prospective cohort study

OBJECTIVES

The study aimed to define the accuracy of intraoperative frozen section (FS) for the detection of metastases in sentinel lymph node biopsy (SLNB) and describe the pattern of lymph node (LN) spread and relation to molecular classifiers in patients with high-grade endometrial cancer (EC).

METHODS

We performed a secondary outcome of clinicopathologic data from the Sentinel Lymph Node Biopsy versus Lymphadenectomy for Intermediate- and High-Grade Endometrial Cancer Staging (SENTOR) prospective cohort study evaluating SLNB in patients with clinical stage I high-grade EC (ClinicalTrials.gov ID: NCT01886066). The primary outcome was the sensitivity of FS of the sentinel lymph node (SLN) specimen, compared to a standardized ultrastaging protocol. Secondary outcomes included the pattern and characteristics of LN spread.

RESULTS

There were 126 patients with high-grade EC with a median age of 66 years (range:44-86) and a median Body Mass Index (BMI) of 26.9 kg/m² (range:17.6-49.3). FS was performed on surgical specimens from 212 hemipelves; SLNs were identified in 202 specimens (95.7%) and fatty tissue alone was identified in 10 specimens (4.7%). Of the 202 hemipelves in which SLNs were identified, 24 were positive for metastatic disease on final pathology. Initial FS correctly identified only 12, yielding a sensitivity of 50% (12/24, 95% CI 29.6-70.4) and a negative predictive value of 94% (178/190, 95% CI 89-96.5). A total of 24 patients (19%) had LN metastases: 16 (13%) had isolated pelvic metastases, 7 (6%) had both pelvic and para-aortic metastases and 1 (0.8%) had an isolated para-aortic metastasis.

CONCLUSIONS

Intraoperative FS of SLNs in high-grade EC patients has poor sensitivity. Since isolated para-aortic metastases are rare, para-aortic lymphadenectomy may be omitted in patients in which SLNs were successfully mapped to the pelvis.

Cervical re-injection of indocyanine green to improve sentinel lymph node detection in endometrial cancer

OBJECTIVES

To evaluate the role of cervical re-injection of indocyanine green (ICG) to increase the detection rate of sentinel lymph node (SLN) in patients with endometrial cancer (EC) who underwent robotic-assisted surgical staging.

METHODS

We retrospectively identified consecutive EC patients undergoing robotic-assisted staging with SLN biopsy at our Institution between June 2016 and April 2020. Patients were excluded if they had open abdominal surgical approach, neoadjuvant chemotherapy, and advanced stage [International Federation of Gynecology and Obstetrics (FIGO) stage III-IV] at diagnosis. According to our SLN protocol, in case of either unilateral or no SLN detection, we performed an ipsilateral or bilateral cervical re-injection of ICG.

RESULTS

In total, 251 patients meeting inclusion criteria were included in the analysis. At first injection, bilateral detection was achieved in 184 (73.3%), unilateral detection in 57 (22.7%), and no detection in 10 (4.0%) patients. Cervical re-injection was performed in 51 of 67 patients with failed bilateral mapping. After cervical re-injection, bilateral detection rate increased to 94.5% (222/235), while unilateral and no detection were 5.1% (12/235) and 0.4% (1/235), respectively.

CONCLUSIONS

Our results suggest that cervical re-injection of ICG, in case of failed bilateral mapping of SLN, brings about a significant improvement in SLN detection rates, therefore reducing the number of side-specific required lymphadenectomies.

Lymph node evaluation in endometrial cancer: how did it change over the last two decades?

Endometrial cancer (EC) is the most common gynecological malignancy in developed countries, and surgery represents the pivotal part of treatment. Hysterectomy and salpingo-oophorectomy allow removing the primary tumor and defining patients at higher risk, who might benefit from adjuvant therapies. Minimally invasive surgery is associated with superior postoperative outcomes and represents a safe and effective approach for surgical staging of EC. The lymph node status evaluation in EC is still a matter of debate. Over the last twenty years much has changed, moving from a full systematic pelvic and paraaortic lymphadenectomy for staging purpose to the removal of the pelvic (with or without paraaortic) lymph nodes only in selected EC classes of risk. Two randomized trials failed to demonstrate survival benefits of lymphadenectomy in case of apparent early stage EC; however, its prognostic role has never been questioned. At present, with the aim of reducing the surgical-related morbidity, sentinel node mapping is emerging as a safe and valid alternative to lymphadenectomy for EC staging, demonstrating high accuracy and an increased detection of lymph nodes metastasis. Here, we performed a review of the most significant studies, which supported the changes in the lymph node status evaluation for EC over the last two decades.

Standard ultra-staging compared to one-step nucleic acid amplification for the detection of sentinel lymph node metastasis in endometrial cancer patients: a retrospective cohort comparison

INTRODUCTION

The objective of this study was to compared standard ultra-staging (SU) with one-step nucleic acid amplification (OSNA) for the detection of sentinel lymph node (SLN) metastasis in women with apparent uterine-confined endometrial cancer.

METHODS

All women underwent SLN identification with complete surgical staging. All SLNs were cut perpendicular to the long axis and two adjacent 5 µm sections were cut at each of two levels 50 µm apart. At each level, one slide was stained with hematoxylin and eosin and the other with immunohistochemistry using the AE1/AE3 anti-cytokeratin antibody, as well as one negative control slide for a total of five slides per block. For OSNA analysis, the 2 mm sections of the lymph nodes were homogenized to form a lysate. The lysate was then centrifuged and inserted into the RD 100i instrument where the isothermal amplification of CK19 mRNA was executed.

RESULTS

Of the 396 patients included in the retrospective analysis, 214 were in the SU group, and 182 in the OSNA group. Overall 869 SLNs were identified (490 SU, 379 OSNA). Sixty patients exhibited SLN metastasis (34 SU, 26 OSNA). Macrometastasis, micrometastases, and isolated tumor cells (ITC) were 5.1%, 4.1%, and 0.2%, respectively, in the US group, and 2.4%, 6.3%, and 0.1%, respectively, in the OSNA group (p=0.022).

CONCLUSIONS

The OSNA assay detected a higher rate of micrometastasis and a lower rate of macrometastasis and ITC when compared with SU. The clinical and prognostic impact of ITC is debatable and controversial. Further studies are needed to clarify the respective roles of the OSNA and SU methods, and the possible role of ITC in the prognosis of patients with apparent early-stage endometrial cancer.

Frozen section examination of sentinel lymph nodes can be used as a decisional tool in the surgical management of early cervical cancer

INTRODUCTION

Sentinel lymph node (SLN) detection has been shown to be accurate in detecting lymph node involvement in early-stage cervical cancer. The objective of this study was to evaluate the accuracy of frozen section examination in the assessment of SLN status, with the aim of adequately driving the intra-operative decision.

METHODS

We designed a retrospective study including patients from two comprehensive cancer centers between January 2001 and December 2018 with early-stage cervical cancer (IA1-IB2 according to International Federation of Gynecology and Obstetrics (FIGO) 2018) undergoing SLN dissection. The SLN procedure was performed using a cervical injection with technetium-99m combined with blue dye or indocyanine green in most cases.

RESULTS

A total of 176 patients fulfilled inclusion criteria. Bilateral mapping was detected in 153 (86.7%) of them. Nineteen of these patients (12.4%) had SLN involvement: 13 with macrometastases, three with micrometastases and three with isolated tumor cells (ITC). Macrometastatic disease was missed on frozen section in 3/13 FIGO 2018 stage IIIC patients. The three patients with ITC were also missed by frozen section examination.Considering only macrometastases as lymph node involvement, frozen section sensitivity was 76.9% (95% CI 49.7 to 91.8) and negative predictive value (NPV) was 97.9% (95% CI 94.0 to 99.3) in patients with bilateral detection. Including micrometastases, sensitivity was 81.2% (95% CI 57.0 to 93.4) and NPV remained at 97.9% (95% CI 93.9 to 99.3).

CONCLUSIONS

With a prevalence of final-stage IIIC in patients with pre-operative early-stage cervical cancer of the order of 10% in this series, the NPV of frozen section examination of SLN is very high, with an inferior limit of the CI superior to 94%. Diagnostic accuracy remains acceptable even if micrometastases are considered. The impact of missed ITC has not been established. Frozen section examination can be incorporated in the intra-operative decision algorithm.

Role of lymphadenectomy in endometrial cancer with nonbulky lymph node metastasis: Comparison of comprehensive surgical staging and sentinel lymph node algorithm

OBJECTIVES

To compare survival and progression outcomes between 2 nodal assessment approaches in patients with nonbulky stage IIIC endometrial cancer (EC).

METHODS

Patients with stage IIIC EC treated at 2 institutions were retrospectively identified. At 1 institution, a historical series (2004-2008) was treated with systematic pelvic and para-aortic lymphadenectomy (LND cohort). At the other institution, more contemporary patients (2006-2013) were treated using a sentinel lymph node algorithm (SLN cohort). Outcomes (hazard ratios [HRs]) within the first 5 years after surgery were compared between cohorts using Cox models adjusted for type of adjuvant therapy.

RESULTS

The study included 104 patients (48 LND, 56 SLN). The use of chemoradiotherapy was similar in the 2 cohorts (46% LND vs 50% SLN), but the use of chemotherapy alone (19% vs 36%) or radiotherapy alone (15% vs 2%) differed. Although there was evidence of higher risk of cause-specific death (HR, 2.10; 95% CI, 0.79-5.58; P = 0.14) and lower risk of para-aortic progression (HR, 0.27; 95% CI, 0.05-1.42; P = 0.12) for the LND group, the associations did not meet statistical significance. The risk of progression was not significantly different between the groups (HR, 1.27; 95% CI, 0.60-2.67; P =0 .53). In parsimonious multivariable models, high-risk tumor characteristics and nonendometrioid type were independently associated with lower cause-specific survival and progression-free survival.

CONCLUSIONS

In EC patients with nonbulky positive lymph nodes, use of the SLN algorithm with limited nodal dissection does not compromise survival compared with LND. Aggressive pathologic features of the primary tumor are the strongest determinants of prognosis.

PET-CT scan in the preoperative workup of early stage intermediate- and high-risk endometrial cancer

Objectives: To evaluate positron emission tomography-computed tomography (PET-CT) for the preoperative management of early-stage intermediate- and high-risk endometrial cancer (EC).Study design: Data of patients with intermediate- and high-risk early-stage EC were retrieved from a prospectively collected database. Patients with preoperative PET-CT followed by surgical staging including pelvic lymphadenectomy were analyzed. Diagnostic performance for lymph node (LN) metastasis was evaluated.Results: Overall, 45 patients were included: 27 (60%) and 18 (40%) with intermediate- and high-risk EC, respectively. Four patients (8.8%) had LN metastasis, three correctly identified at PET-CT, yielding a sensitivity of 75% (95% CI 21.9-98.7). Among 41 patients (91.2%) without LN metastasis, 38 had negative PET-CT with specificity of 92.7% (95% CI 78.9-98.1). The negative predictive value (NPV) was 97.4% (95% CI 84.9-99.9) and the positive predictive value was 50% (95% CI 13.9-86.1).Conclusions: The utility of PET-CT is limited by the low sensitivity for LN metastasis in intermediate- and high-risk early-stage EC, that may impede to consider PET-CT alone an adequate alternative to surgical retroperitoneal staging by lymphadenectomy or sentinel LN biopsy. However, the high diagnostic accuracy, specificity and NPV might support its adoption to improve the diagnostic accuracy of the sentinel LN algorithm.

Robotic sentinel node mapping in clinical stage 1 endometrial cancer using methylene blue dyes using the robotic platform

PURPOSE

Endometrial cancer is a surgically staged cancer. We examined our preliminary experience with sentinel lymph node (SLN) mapping in early stage endometrial cancer using methylene blue dyes.

METHOD

Retrospective review of all clinically stage 1 endometrial cancer staged surgically using the robotic platform. Logistic regression models were built to predict nodal metastasis taking into account age, grade, histology, depth of myometrial invasion, cervical involvement, and use of SLN mapping.

RESULTS

Four hundred sixty-nine patients were reviewed. Sixty patients had SLN mapping (13%). Four hundred nine patients underwent standard lymphadenectomy with five documented nodal metastasis (1.2%). Five nodal metastasis (8.3%) were seen in the SLN patients. In the logistic model, the application of SLN mapping was significantly associated with diagnosed nodal metastasis (OR 7.74; 95% CI, 2.04-29.3; P = .003) together with nonendometroid histology (OR 5.05; 95% CI, 1.27-20.12; P = .022).

CONCLUSION

SLN mapping protocol using methylene blue significantly identifies more nodal metastasis than standard lymphadenectomy.

Ultrastaging of negative pelvic lymph nodes to decrease the true prevalence of isolated paraaortic dissemination in endometrial cancer

OBJECTIVE

This study aimed to determine the prevalence of occult pelvic lymph node metastasis in patients with endometrial cancer (EC) with isolated paraaortic dissemination who underwent pelvic and paraaortic lymphadenectomy.

METHODS

From 2004 to 2008, patients undergoing surgery for EC at our institution were prospectively treated according to a validated surgical algorithm relying on intraoperative frozen section. For the current study, we re-reviewed pathologic slides obtained at the time of diagnosis and performed ultrastaging of all negative pelvic lymph nodes to assess the prevalence of occult pelvic lymph node metastasis.

RESULTS

Of 466 patients at risk for lymphatic dissemination, 394 (84.5%) underwent both pelvic and paraaortic lymphadenectomy. Of them, 10 (2.5%) had isolated paraaortic metastasis. Pathologic review of hematoxylin-eosin-stained slides identified 1 patient with micrometastasis in 1 of 18 pelvic lymph nodes removed. Ultrastaging of 296 pelvic lymph nodes removed from the 9 other patients (median [range], 32 [20-50] nodes per patient) identified 2 additional cases (1 with micrometastasis and 1 with isolated tumor cells), for a total of 3/10 patients (30%) having occult pelvic dissemination.

CONCLUSIONS

Ultrastaging and pathologic review of negative pelvic lymph nodes of patients with presumed isolated paraaortic metastasis can identify occult pelvic dissemination and reduce the prevalence of true isolated paraaortic disease. In the era of the sentinel lymph node (SLN) algorithm for EC staging, which incorporates ultrastaging of the SLNs removed, these findings demonstrate that use of the SLN algorithm can further mitigate the concern of missing cases of isolated paraaortic dissemination.

Sentinel Lymph Node Biopsies in Endometrial Cancer: Practice Patterns among Gynecologic Oncologists in the United States

STUDY OBJECTIVE

To evaluate practice patterns among gynecologic oncologists with regard to sentinel lymph node injection and biopsy in endometrial cancer.

DESIGN

An observational study with no control group.

SETTING AND PATIENTS

Active members of the Society of Gynecologic Oncology.

INTERVENTIONS

After institutional review board approval, we performed an online survey among active members of the Society of Gynecologic Oncology. Members were contacted via e-mail and their answers anonymously captured. Study data were collected using REDCap (REDCap developed by Vanderbilt University, Nashville TN).

MEASUREMENTS AND MAIN RESULTS

Three hundred eighteen of 1216 listed members completed the online survey. The majority of respondents (82.7%) perform sentinel lymph node sampling for endometrial cancer staging. Most technical aspects of sentinel lymph node sampling were consistently applied by the vast majority of respondents, including the choice of indocyanine green as a lymphatic tracer (97.3%) and its injection into the cervix (100%). Other technical aspects of sentinel lymph node sampling, such as the depth of injection, varied among respondents. Although 50.9% of the respondents perform an intraoperative assessment of the uterus by frozen section, only 17.9% assess sentinel lymph nodes by frozen section and/or touch prep. Some of the respondents' approaches are based on limited data, including (1) the use of sentinel lymph node injection and biopsy for high-risk histologies (performed by 69%-75% of the respondents dependent on the histology), (2) omitting side-specific completion lymphadenectomy in the absence of sentinel node mapping (in up to 57.8%), or (3) when lymph node metastases are present (in 39.9%).

CONCLUSION

In summary, despite the growing use of sentinel lymph node injection and biopsy in endometrial cancer, practice patterns vary considerably among providers sampled by this survey. Some of the decisions are based on limited evidence and, in some instances, deviate from current published guidelines.

Comparison of sentinel lymph node detection performances using blue dye in conjunction with indocyanine green or radioisotope in breast cancer patients: a prospective single-center randomized study

Objective:

This randomized study aimed to compare the clinical efficacy between the novel dual tracer composed of indocyanine green (ICG) and blue dye (BD) and the conventional dual tracer composed of radioisotope and BD for sentinel lymph node (SLN) mapping in patients with breast cancer.

Methods:

This study enrolled 471 clinically lymph node-negative patients with primary breast cancer. All patients underwent mastectomy, and those undergoing sentinel lymph node biopsy (SLNB) were randomized to receive blue dye plus radioisotope (RB group) or BD plus ICG (IB group). The detection performances on SLN identification rate, positive SLN counts, detection sensitivity, and false-negative rate were compared between the two groups.

Results:

In the IB group, 97% (194/200) of the patients who underwent the ICG and BD dual tracer injection showed fluorescent-positive lymphatic vessels within 2–5 min. The identification rate of SLNs was comparable between the IB group (99.0%, 198/200) and the RB group (99.6%, 270/271) (P = 0.79). No significant differences were observed in the identification rate of metastatic SLNs (22.5% vs. 22.9%, P > 0.05, RB group vs. IB group, the same below), positive SLN counts (3.72 ± 2.28 vs. 3.91 ± 2.13, P > 0.05), positive metastatic SLN counts (0.38 ± 0.84 vs. 0.34 ± 0.78, P > 0.05), SLNB detection sensitivity (94.4% vs. 92.5%, P > 0.05), or false-negative rate (5.6% vs. 7.5%, P > 0.05) between the two groups.

Conclusions:

ICG can be used as a promising alternative tracer for radioisotope in SLN mapping, and when it is combined with BD in lymphangiography, it offers comparable detection sensitivity compared to the conventional lymphatic mapping strategies that are widely used in clinical practice.